A lot of the information in these appendices is also distributed throughout the book. However, it is brought together in these appendices so you have a handy reference. The appendices also include additional, more detailed information that would disrupt the flow of the book / bloat the contents if included in the main text.
International Bureau of Weights and Measures (BIPM)
A lot of this reference material is a summary of information from the website of the Bureau International des Poids et Mesures (BIPM) – in English, the "International Bureau of Weights and Measures". While the BIPM is an international organisation, the name of the organisation and the titles of related standards – such as the Système International d'Unités (SI) – are in French, because the organisation's headquarters are in France.
Why is the BIPM, and their work, important to you?
The BIPM is the international organisation that oversees international agreements on metrology and associated standards. Metrology is the science of measurement, and because measurement (through observation and experiment) is at the foundation of science, then for you to understand and communicate physics it is important that you understand the work of the BIPM. It is also useful, more generally, for you to be aware of the work of the BIPM and how it impacts the world you live in.
For example, if you buy a kg of sugar, you want to be sure it is a kg of sugar so you are not ripped off!... and then when you bake your cake, if your "cup measure" is not definitely "a cup" you could get the amount of sugar wrong and your cake will not come out right!... grrrr.
Can you think of other examples of the impact of the work of the BIPM on your life? In answering this question, it might help to think of areas of particular interest to you, for example: transport, sport, medicine.
International connections and Australian involvement
The work of the BIPM is endorsed by nearly every country in the world as either a Member State or Associate State. Countries participate in the work of the BIPM through their national metrological bodies. In Australia this is the National Measurement Institute and related organisations. Also, Australian scientists work for, or with, the BIPM.
The BIPM is also responsible for bringing together many international organisations. Of particular interest to you, in studying physics, the BIPM works with the International Union of Pure and Applied Physics (IUPAP) and the International Astronomical Union (IAU).
Of more general interest to you, the BIPM works with organisations such as the International Organization of Legal Metrology (OIML) – important in relation to that kg of sugar you wanted to buy!
The BIPM and your studies in physics
To clearly communicate the results of any measurements you make, while carrying out experiments in physics, you need to use international standards such as those maintained by the BIPM. Similarly, any theoretical work you do should use such standards. So, for example, when you make measurements of length, or work out problems involving length, it is often best to use metres (m).
In many instances, this does not impact the fundamental concepts you are conveying (a length does not change whether you measure, and report it, in metres or chains) but using conventional language and symbols means it is relatively simple and quick for others to understand what you are communicating.
However, the definition of quantities such as the metre, second and kilogram, have become more and more closely tied to the fundamental ways our universe works. So how we define, and use them, are of particular importance in physics, because it deals with how the universe works at the most fundamental level. Therefore, as part of your studies in physics, starting to understand these connections, is important.
For example, the kilogram was only recently redefined (along with the ampere, kelvin and mole, as of 20 May 2019) from being based on a physical reference object (a platinum-iridium cylinder, see image to the right) to being based on fundamental measurements of the universe – for more information see Appendix A - SI Units.